Refrigerating system.



A. T. MARSHALL.

REFRIGERATING SYSTEM- APPLICATION FILED JUNE 18, 1908.

1,061,66 Patented Aug. 29, 1911.

WITNESSES. llVI/ENTOH unrn- 1 ans ATEN' arm,

ALBERT T. MARSHALL, WE HARTFORD, CONNECTICUT, ASSIGNOR TO THE AUTOMATIC REFRIGERATING COMPANY, OF HARTFORD, CONNECTICUT; A CORPORATION OF NEW. JERSEY.

nEFnIsnnATING SYSTEM.

nooneea.

To allwhom it may concern:

'Be it known that I, ALBERT T. MARSHALL, a citizen of the United States, and a resident of Hartford, Hartford county, State .of Connecticut, have invented certain new and useful Improvements in Refrigerating Systems, of which the fol'lowing is a full, clear, and exact description.

My invention relates to refrigerating systems in which a fluid, such as, for instance, ammonia, is used as a refrigerant byfirst compressing and then expanding it.

In particular, my invention relates, in

i such plants, to the manner in which the refrigerant is distributed 'to the several distributing chambers so that these chambers may be cooled as required, independent of each other.

through the coils of which the refrigerant asses last owin to the reater resistance 3 offered by the long pipe to this latter'chamber. Consequently, the devices cutting off .the refrigerant after the proper low temperature is reached must be placed so that the refrigerant is cut off only' after the proper temperature has been reached in the last chamber, thus causing the other chambers to assume too low atemperature, or, in

case of the cut-off device operating at the.

proper temperature of one of the first chambers, to leave the last chamber without the proper refrigeration. Furthermore, in case the different chambers should require a different temperature, it is impossible, in the arrangement above referred to,-to obtain a certain temperature in one of these chambers without disturbing therefrigeration of the other chambers. In my novel arrange-.

ment, all these difficulties and disadvantages are overcome, and 'each chamber may be cooled to the temperature desired where-. after the refrigerant is cut off from this chamber without disturbing the refrigera- Specification of Letters Patent. Patented Aug.- 29, 19111. Application filed June 18, 1908.

Serial No. 439,143.

tion of the other chambers which may still require further supply of refrigerant.

Another particular feature of my system is, that the compressor, supplying the re frigerant to thefsystem is automatically stopped only after every chamber has reached its proper temperature and also automatically started again whenever any of the chambers should require further refrigeration.

I provide suitable means for each chamber controlled by the means for cutting off the refrigerating supply fort-his chamber, which meanstend to stop the operation of the compressor and which are arranged soas to operate in parallel to each other, so that the compressor will be stopped after the last chamber has been cut off, and-sothatthe compressor will be started again whenever the rising temperature in one of the chambers should call for a supply of refrigerant. Also, safety means may lee-provided always the maximum amount of refrigerant is admitted to the coil, which the latter can evaporate according to its temperature, so

that at notime any appreciable amount of liquid refrigerant can reach the low pres sure side of the system.

In the drawing I have illustrated diagrammatically how my invention may be reduced to practice, all detail construction, however, of the different devices required therein. being omitted" as they are well known to the art.

In-the drawings, 1,. 2 refrigerating chambers. v

4 is a compressor with the usualcondenser and receiver (which I have for the sake of simplicity merely indicated by a rectangular element 4*), the compressor supplying nefrigerantof high pressure to-pipe 5. 7

25 are expansion valves which may be of any suitable kind known in the art. From and are different the valves 25' the-refrigerant is discharged into pipes8, to each of which is connected a stop valve 6 which controls the supply to the expansion system, consisting, as shown, of coils 10 in each chamber. A pipe 11,- running through all chambers, connects the other ends of coils 10 in parallel, thus leading the refrigerant back to the compressor 4 on the low pressure side of the system.

In each of chambers 1, 2 and 3 is provided a thermostat 12 which controls its stop valve 6 by means of pressure fluid of any kind, such as for instance air or water. in any well known manner, the controlling fluid for the thermostat being supplied through pipe 13, so that the thermostat 12 for each chamber is connected by a pipe 14 in parallel to pipe 13. From thermostats tor starter 19 for the motor (not shown),

driving the compressor 4. If a high tension circuit should be used for operating the solenoid, a resistance 20 may be provided in this circuit in order not, to overload'the coil, which resistance may be shunted by switch 21 so long as solenoid 18 is disengaged, the switch being opened by suitable means after the solenoid has thrown in the motor starter 19. To thepressure system',,operating stop valve 6 is further connected a circuit breaker 23 which may be operated in any suitable manner by the pressure fluid controlled by the thermostat, so that when stop valve 6 is closed by the action of the thermostat, circuit breaker 23 .will open at the same time. Such a connection is shown for instance in the drawing, in which'circuit breaker 23 is connected with .any" suitable moving part of valve'6, which connection is, however, only advisable in case' the surroundings of the valve can be keptsufiiciently dry, so as not-to'disturb the insulation..

The solenoid ing the plus pole the current flows through solenoid 18, resistance 20 (or switch 2l as maybe the case), thence through the circuit breaker 23 of any of the stop valves .6,

which are all in parallel to the line, thence through a circuit breaker 22 of pressure gage 16 and back to the minus poles. It is obvious that circuit breaker 23 may also control small relays which in turn control the motor starter. These forms of control being, however, so well knownin the art, their description and illustration have been omitted in the present application.

circuit ,isas follows: Leav- The expansion valve 25, previously referred to,is preferably of special construction so that its operation may be controlled by the temperature of the expanded gases wherr leaving the expansion coils 10, so that at any time the maximum amount of refrigerant is supplied by the valve 25 to its coil which the coil can evaporate. For this purpose I provide a thermostatic chamber 26 at the end of the coil system 10, through which chamber the end of coil 10 passes before joining the return main 11. Chamber 26 contains a suitable charge of fluid, highly responsive to expansion and contraction by the increase or decrease in temperature, preferably ammonia, so that this fluid is acted upon by the temperature of the gas in the refrigerating coil. Chamber 26 is con nected by pipe 29 with a suitable element of expansion valve 25, so as to cause the am monia charge contained in chamber 26 to throttle the feed of valve 25 as it cools. The construction of these so called thermostatic expansion valves, such as is indicated at 25, being well known in the art, a detail description and illustration is omitted, and the expansion valve and thermostatic chamber are merely indicated in their relative position to each other, so as to show how these elements may be disposed in my novel refrigerating system. The particular advantage of employing this kind of expansion valve and fluid thermostat in each chamber is that these valves keep the refrigerating coils which they control frosted throughout their whole length by supplying, as pointed out above, all of the refrigerant which the coils can evaporate instead of supplying it at a fixed back pressure with, a part ofthe coil not frosted as would be the case if for instance one expansion valve common to all chambers were used. The individual expansion valve 26 will keep the coil in each chamber frosted until the temperature of the chamber is reduced sufliciently for the chamber thermostat 12 to act and. close the special stop valve 6, shutting off entirely all further refrigeration of these chambers, and breaking at the same time the circuit at 23, as described,-until the temperature of a. the chamber has risen sufficiently to again operate the stop valve'6 to turn on the re frigeration. The fact that expansion valve 26 keeps the whole length of its coil frosted throughout the whole period duringwhich the chamber-requires refrigeration, does not necessarily mean that this valve 25 remains full open; but the coil being first-warm, and thus able to evaporate probably the maxi-' mum amount of refrigerant-which the expansion valve 25,can furnish, will soon cool, so that also the refrigerant therein cools. Coil 10 thus loosinga part of its evaporating capacity isunable to .take care of the full amount of liquid refrigerant, supplied by the manner described above throttles the refrigerant supply 25, the two elements being adjusted relatively to each other and to the size of the coil that by such throttling ala ways the maximum amount of refrigerant is supplied which the coil can evaporate at a prevailing temperature of the coil.

The operation of the Whole system is as follows: Assuming each of the chambers should require refrigeration, the thermostat 12 of each chamber will cause its stop valve to open, which will at the same time cause circuit breaker 23 to close. At this time circuit breaker 22 of pressure gage 16 will also be closed, so that the solenoid circuit is completed and solenoid 18 throwsthe motor operated compressor 4' into operation. Coils 10 being then comparatively warm and also the thermostatic fluid in chamber 26 being warm, expansion valves 25 .are wide open. The refrigeration now takes place in each chamber in the manner previously described. If now, for instance, chamber /'2 should be sufliciently cooled, its thermostat 12, which is very accurately responsive to the temperature in the chamber, causes stop valve 6* to close and thus to shut off entirely the refrigerant supply to coil system 10 of this chamber. The closing of stop valve 6*, as also previously stated, at the same time causes circuit breaker 23 to open. The opening of circuit breaker 23 in chamber 2, however, will not cause the compressor 4 to stop, since I c 1 the circuit breakers 23 in the other chambers are still closed. Only after the refrigerant in all chambers has been shut off from their respective coils is the solenoid circuit completely interrupted and by these means the compressor is stopped.

It may happen that the high pressure side of the system assumes, through any cause, an undue and dangerously high pressure. In this case pressure gage 16 comes into action and causes its circuitbreaker 22'to open and to interrupt the solenoid circuit, thus stopping the operation of the compressor. This action takes place independently of the refrigeration of the different chambers, that is to say, no matter whether they are properly cooled at the time or not, because circuit breaker 22 is in series with circuit breakers 23 of all chambers. The compressor 4 now remains at rest until normal pressure is restored in the system which permits circuit breaker 22 to close, and thus return the control of the starting or stopping of the motor to the individual thermostats 12 of each chamber.

It will be clearly seen that in my novel refrigerating system each chamber may receive the refrigeration desired independently of the temperature conditions of the other chambers, and the refrigeration may be cut off or turned on in each chamber without disturbing the refrigeration of the other chambers; furthermore it will be seen that in case none of the chambers should require refrigeration, the operation of the compressor will be stopped automatically and thrown in automatically if any of the chambers should require refrigeration. It is also obvious that I chamber within certain desired limits, and

while it is admitted that such thermostats have been used heretofore in the art as a sole control of refrigerating chambers, still such regulation is possible only within very wide limits, which for modern requirements of refrigeration would be totally insufficient. The reason for this deficiency is obvious because the thermostatic charge is solely affected by the temperature of the refrigerant and therefore in case of comparatively large chambers it can not respond to the temperature conditions in such chambers, particularly not at places remote from the coil. On the other hand thermostats of the character such as thermostat 12, which may be placed in any suitable place in the chamber can be made,

as is well known in the art, to respond within very narrow limits to temperature changes. Thus b the combination of the two thermostatic evices I maintain at any time the exact temperature of the chamber desired, and also the maximum efliciency of the coil at any given temperature.

\Vhile I have shown in the drawing a speoificarrangement of the different auxiliary devices comprising the refrigerating system, I do not wish to limit myself to anyparticular form of device such asstop valves, expansion valves, thermostats and the like, which, as has been previously stated are Well known inthe art, in themselves, the,

- of the other chambers, and in maintaining not only the exact temperature in each chamber but in also maintaining the maximum efficiency of the coil at a given temperature. What I claim is:

1. In a refrigerating plant having a plu rality of refrigerating chambers, the combination with expansion coilsfin said chambers, a compressor supplying the refrigerantto said coils in parallel, means for each chamber, cont-rolled by. the temperature of 1,5 nation with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallel, means foreach chamber, controlled by thetemperature of the refrigerant when leaving said coils, for supplying the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermostats in said chamber; of valves directly controlled by said thermostats for regulating the refrigerant su ply to each chamber to maintain the pre etermined temperature of each chamber, and means .for automatically starting the operation of said compressor, when any of said chambers require refrigeration.

3. In a refrigerating plant having a plurality of refrigerating chambers, the combination with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallel, expansion-valves for each chamber controlled by the temperature of the refrigerant'when leaving said coils for supplying the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermo- 40 stats in said chambers; of valves directly controlled by said thermostats for regulating the refrigerant supply to each chamber to maintain the predeterminedtemperature of I each chamber, and means for automatically stopping the operation of said compressor, when all of said chambers have assumed the desired temperature. 1 1 y e 4;. In a refrigerating plant having a plu-' rality of refrigerating chambers, the combi- 0 nation with expansion coils in said chambers, a compressor supplying the refrigerant to saidcoils in parallel, expansion valves for each chamber controlled by the temperature of the-refrigerant when leaving said coils for supplying the maximum amount of refrigerant whjchthe coils can evaporate according to their temperature, and thermostats in said chambers; of valves directly controlled by said thermostats for regulating the refrigerant supply to each chamber to maintain the predetermined temperature of each chamber, and means for automatically starting the operation of said compressor,-

when any of said chambers require refrigeration.

5. In a refrigerating plant having a plurality of refrigerating chambers, the combination with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallel, means for each chamber controlled by the temperature of the refrigerant when leaving said coils for supplying the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermostats in said chambers; of valves directly controlled by said'thermcstats for regulating the refrigerant supply to each chamber to maintain the predetermined temperature of each chamber, and means controlled by said thermostats for stopping the operation of said compressor, when all ofsaid chambers have assumed their desired temperature.

6. In a refrigerating plant having a plurality of refrigerating chambers, the comblnation with expansion coils in said chambers, 'a compressor supplying the refrigerant to said coils in parallel, means for' each chamber controlled by the temperature of the refrigerant when leaving said coils for supplying the maximum amount of refrigerant .which the coils can evaporate according to their temperature, and thermostats in said chambers; of valves directly controlled by said thermostats for regulating the refrigerant supply to each chamber to main-' tain the predetermined temperature of each chamber, and means controlled by said thermostats for starting the operation of said compressor, when any of said chambers require refrigeration.

7 In a refrigerating plant having a plurality of refrigerating chambers, the combination with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallel, an expansion valve for each chamber controlled by the temperature of the refrigerant when leaving said coils for supplying the maximum amount ofrefrigerant which the coils can evaporate according to their temperature, and thermostats in said chambers; of valves directly controlled by said thermostats for regulating the refrigerant supply to each chamber to maintain the predetermined temperature of each chamber, and means controlled by said thermost-atsfor stopping theoperation of said compressor, when all of said chambers have assumed their desired temperature. I l

8. In a refrigerating plant having a plurality of refrigerating chambers, the combination with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallehan expansion valve for each chamber controlled by the temperature of the refrigerant when leaving said coils for supplying the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermostats insaid loo ; chambers; of valves directly controlled "by said thermostats for regulating the refrigerant supply to each chamber to maintain the predetermined temperature of each chamber,

perature responsive fluid and suitablyv con nected with said expansion valve, to permit said fluid to act upon said expansion valve to supply the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermostats in said chambers; of stop valves directly controlled by said thermostats for,

. regulating the refrigerant supply to each temperature.

chamber to maintain the predetermined temperature of each chamber and means controlled by said thermostats for stopping the operation ofsaid compressor, when all of said chambers have assumed their desired 10. In a refrigerating plant having a plurality of refrigerating chambers, the combination with expansion coils in said chambers, a compressor supplying the refrigerant to said coils in parallel, an expansion 1 valve for each chamber and a thermostatic chamber surrounding the expansion coils in each chamber at the point where the refrigerant leaves saidcoil and adapted to contain temperature responsive fluid and suitably connected with said expansion valve, to permit said fluid-to act upon-said expansion valve to supply the maximum amount of refrigerant which the coils can evaporate according to their temperature, and thermostats in said chambers; of stop valves di-' rctly controlled by said thermostats for regulating the refrigerant supply to each chamber to maintain the predetermined temperature of each chamber and means controlled by said thermostats for/starting I the operation of said compressor, when any fee of said chambers require'refrigeration.

11.. -In apparatus of'the character de scribed, the combination of a refrigeratlng chamber, fluid expansion system, means for supplying refrigerating fluid thereto, a valve controlling the supply of fluid to said system, means responsive to the temperature at the delivery end of said system for controlling said valve to supply the maximumamount of refrigerant which can be evaporated in the system, a second valve controlling the supply of fluid to said system, and means responsive to the temperature in the refrigerating chamber for controlling saidsecond valve.

' 12. In apparatus of the character described, the combination of a refrigerating chamber, fluid expansion system, means for supplying refrigerating fluid thereto, a valve controlling the supply offluid to said system, means responsive to the temperature at the delivery end of said system for controlling said valve' to supply the maximum amount of refrigerant which can be evap-- orated in the system, a second valve controllingthe supply of fluid to said system in series with the first valve, and means responsive to the temperature in the refrigcrating chamber for controlling said second valve.

13'. In apparatus of the character described, the combination of a refrigerating chamber, fluid expansion system, a pump for supplying refrigerating fluid thereto a valve controlling the supply of fluid to sziid system, means responsive to the temperature at the delivery end of said system for controlling said valve to supply the maximum amount of refrigerant which can be evaporated in the system, a second valve controlling thesupply of fluid to said system,'and means responsive to the temperature in the refrigerating chamber for controlling said second'valve, and stopping the pump.

14. In apparatus of the character de scribed, the combination of a refrigerating .chamber, fluid expansion system, a pump for su lying ,refrigeratingfiuid thereto, a valve diitrolling the supply of fluid to said system, means responsive to the temperature at the delivery end of said system for controlling said valveto supply the maximum amount of refrigerant which can be evaporated in the system,a-second valve controlling the supply of fluid to said" system, and means responsive to the temperature in the refrigerating chamber for controlling said second valve and startin the pump.

ALBERT T. MARS ALL.

, Witnesses:

M. F. DonovA-n, S. H. MARSHALL. c 

